Merging along object hierarchies

ABSTRACT

Some embodiments of the present invention include a method for merging nodes in hierarchies and include receiving, by a database system, a request to merge a first node in a first hierarchy of a plurality of nodes into a second node, the first node in the first hierarchy having child nodes; determining, by the database system, whether the merge request violates each of a plurality of constraints, the plurality of constraints comprising circular dependency of nodes, deleted node and ordering of nodes; and re-parenting, by the database system, in response to a determination that the merge request does not violate each of the plurality of constraints, the child nodes of the first node in the first hierarchy of nodes to the second node in response to the merging of the first node into the second node.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

FIELD OF THE INVENTION

One or more implementations relate generally to data processing, and more specifically for merging data organized in hierarchies.

BACKGROUND

The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed inventions.

Data associated with an organization may be merged for various reasons. One example for merging is to avoid redundancy. Data may be organized using hierarchy and may be related to one another. Merging data organized in hierarchy is complex and can present many issues including, for example, consistency of data in the hierarchy before and after the merge.

BRIEF SUMMARY

For some embodiments, a method for merging nodes in hierarchies may include receiving, by a database system, a request to merge a first node in a first hierarchy of a plurality of nodes into a second node, the first node in the first hierarchy having child nodes; determining, by the database system, whether the merge request violates each of a plurality of constraints, the plurality of constraints comprising circular dependency of nodes, deleted node and ordering of nodes; and re-parenting, by the database system, in response to a determination that the merge request does not violate each of the plurality of constraints, the child nodes of the first node in the first hierarchy of nodes to the second node in response to the merging of the first node into the second node. Other aspects and advantages of the present invention can be seen on review of the drawings, the detailed description and the claims, which follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The included drawings are for illustrative purposes and serve only to provide examples of possible structures and process steps for the disclosed techniques. These drawings in no way limit any changes in form and detail that may be made to embodiments by one skilled in the art without departing from the spirit and scope of the disclosure.

FIG. 1 is example diagram of a computing system that may be used with some embodiments.

FIG. 2 is an example diagram of a network environment that may be used with some embodiments.

FIGS. 3A-3J are example diagrams showing hierarchies that may be resulted from merging of a victim node to a master node, in accordance with some embodiments.

FIGS. 4A-4B are example diagrams showing soft delete node in a merge, in accordance with some embodiments.

FIG. 5 shows an example implementation of a merge module, in accordance with some embodiments.

FIG. 6A shows a flowchart of an example process for verifying the requirements to merge nodes in hierarchies, in accordance with some embodiments.

FIG. 6B shows a flowchart of an example process for merging nodes after the requirements are satisfied, in accordance with some embodiments.

FIG. 7 shows example scripts written in PL/SQL that may be used to merge nodes in hierarchies, in accordance with some embodiments.

FIG. 8A shows a system diagram illustrating architectural components of an applicable environment, in accordance with some embodiments.

FIG. 8B shows a system diagram further illustrating architectural components of an applicable environment, in accordance with some embodiments.

FIG. 9 shows a system diagram illustrating the architecture of a multitenant database environment, in accordance with some embodiments.

FIG. 10 shows a system diagram further illustrating the architecture of a multi-tenant database environment, in accordance with some embodiments.

DETAILED DESCRIPTION

Various implementations described or referenced herein are directed to different systems, apparatus, methods and computer-readable storage media for merging data organized in hierarchies. In the following description, a hierarchy may include one or more levels, with each level having one or more nodes. The hierarchies and the nodes may be associated with a database system. The term “node” is used in the description to generically refer to a data entity in a hierarchy and its relationship with another data entity in the hierarchy. For example, a node can be a record, an account or a business object. A node to be merged to another node may be referred to as a victim node. A node that the victim node is merged to may be referred to as a master node. A request to merge a victim node to a master node may be received via a user interface or an application programming interface (API). There may be one or more victim nodes in a merge request.

The systems, apparatus, methods and computer-readable storage media for merging data organized in hierarchies will be described with reference to example embodiments. These examples are being provided solely to add context and aid in the understanding of the present disclosure. It will thus be apparent to one skilled in the art that the techniques described herein may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the present disclosure. Other applications are possible, such that the following examples should not be taken as definitive or limiting either in scope or setting.

In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the disclosure, it is understood that these examples are not limiting, such that other embodiments may be used and changes may be made without departing from the spirit and scope of the disclosure.

As used herein, the term “multi-tenant database system” refers to those systems in which various elements of hardware and software of the database system may be shared by one or more customers. For example, a given application server may simultaneously process requests for a great number of customers, and a given database table may store rows for a potentially much greater number of customers.

The described subject matter may be implemented in the context of any computer-implemented system, such as a software-based system, a database system, a multi-tenant environment, or the like. Moreover, the described subject matter may be implemented in connection with two or more separate and distinct computer-implemented systems that cooperate and communicate with one another. One or more embodiments may be implemented in numerous ways, including as a process, an apparatus, a system, a device, a method, a computer readable medium such as a computer readable storage medium containing computer readable instructions or computer program code, or as a computer program product comprising a computer usable medium having a computer readable program code embodied therein.

The disclosed embodiments may include a method for merging nodes in hierarchies and include receiving, by a database system, a request to merge a first node in a first hierarchy of a plurality of nodes into a second node, the first node in the first hierarchy having child nodes; determining, by the database system, whether the merge request violates each of a plurality of constraints, the plurality of constraints comprising circular dependency of nodes, deleted node and ordering of nodes; and re-parenting, by the database system, in response to a determination that the merge request does not violate each of the plurality of constraints, the child nodes of the first node in the first hierarchy of nodes to the second node in response to the merging of the first node into the second node.

The disclosed embodiments may include an apparatus for merging nodes in hierarchies and include a processor, and one or more stored sequences of instructions which, when executed by the processor, cause the processor to receive a request to merge a first node in a first hierarchy of a plurality of nodes into a second node, the first node in the first hierarchy having child nodes; determine whether the merge request violates each of a plurality of constraints, the plurality of constraints comprising circular dependency of nodes, deleted node and ordering of nodes; and re-parent, in response to a determination that the merge request does not violate each of the plurality of constraints, the child nodes of the first node in the first hierarchy of nodes to the second node in response to the merging of the first node into the second node.

The disclosed embodiments may include a machine-readable medium carrying one or more sequences of instructions for merging nodes in hierarchies, which instructions, when executed by one or more processors, may cause the one or more processors to receive a request to merge a first node in a first hierarchy of a plurality of nodes into a second node, the first node in the first hierarchy having child nodes; determine whether the merge request violates each of a plurality of constraints, the plurality of constraints comprising circular dependency of nodes, deleted node and ordering of nodes; and re-parent, in response to a determination that the merge request does not violate each of the plurality of constraints, the child nodes of the first node in the first hierarchy of nodes to the second node in response to the merging of the first node into the second node.

While one or more implementations and techniques are described with reference to an embodiment in which merging operations are implemented in a system having an application server providing a front end for an on-demand database service capable of supporting multiple tenants, the one or more implementations and techniques are not limited to multi-tenant databases nor deployment on application servers. Embodiments may be practiced using other database architectures, i.e., ORACLE®, DB2® by IBM and the like without departing from the scope of the embodiments claimed. Likewise, embodiments may be practiced in cloud-based storage systems that make up an on-demand computing platform such as those provided by Amazon® Web Services.

Any of the above embodiments may be used alone or together with one another in any combination. The one or more implementations encompassed within this specification may also include embodiments that are only partially mentioned or alluded to or are not mentioned or alluded to at all in this brief summary or in the abstract. Although various embodiments may have been motivated by various deficiencies with the prior art, which may be discussed or alluded to in one or more places in the specification, the embodiments do not necessarily address any of these deficiencies. In other words, different embodiments may address different deficiencies that may be discussed in the specification. Some embodiments may only partially address some deficiencies or just one deficiency that may be discussed in the specification, and some embodiments may not address any of these deficiencies.

The described subject matter may be implemented in the context of any computer-implemented system, such as a software-based system, a database system, a multi-tenant environment, or the like. Moreover, the described subject matter may be implemented in connection with two or more separate and distinct computer-implemented systems that cooperate and communicate with one another. One or more implementations may be implemented in numerous ways, including as a process, an apparatus, a system, a device, a method, a computer readable medium such as a computer readable storage medium containing computer readable instructions or computer program code, or as a computer program product comprising a computer usable medium having a computer readable program code embodied therein.

In general, businesses use a CRM (Customer Relationship Management) system (also referred to as a database system or system) to manage business relationships and information associated with the business relationship. For example, this may include customer and prospect contact information, accounts, leads, and opportunities in one central location. The information may be stored in a database as objects. For example, the CRM system may include “account” object, “contact” object and “opportunities” object.

The “account” object may include information about an organization or person (such as customers, competitors, and partners) involved with a particular business. The “contact” object may include contact information, where each contact may be an individual associated with an “account”. The “opportunities” object includes information about a sale or a pending deal. Each object may be associated with fields. For example, the “accounts” object may include fields such as “company”, “zip”, “phone number”, “email address”, etc. The “contact” object may include fields such as “first name”, “last name”, “phone number”, “accountID”, etc. The “accountID” field of the “contact” object may be the ID of the account that is the parent of the contact. The “opportunity” object may include fields such as “amount”, “accountID”, etc. The “accountID” field of the “opportunity” object may be the ID of the account that is associated with the opportunity. Each field may be associated with a field value. For example, a field value for the “zip” field may be “94105”. For some embodiments, the hierarchies described herein may be related to an object and the nodes in the hierarchies may be related to a field in the object. For some embodiments, the systems, methods, apparatus and computer-readable storage media described herein provide ways of managing the hierarchies regardless of the fields used.

FIG. 1 is a diagram of an example computing system that may be used with some embodiments of the present invention. The computing system 102 may be used by a user to log into a server computer system to enable the server computer system to merge data organized in hierarchies and to prevent hierarchy inconsistency in the merged result.

The computing system 102 is only one example of a suitable computing system, such as a mobile computing system, and is not intended to suggest any limitation as to the scope of use or functionality of the design. Neither should the computing system 102 be interpreted as having any dependency or requirement relating to any one or combination of components illustrated. The design is operational with numerous other general purpose or special purpose computing systems. Examples of well-known computing systems, environments, and/or configurations that may be suitable for use with the design include, but are not limited to, personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, mini-computers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like. For example, the computing system 102 may be implemented as a mobile computing system such as one that is configured to run with an operating system (e.g., iOS) developed by Apple Inc. of Cupertino, Calif. or an operating system (e.g., Android) that is developed by Google Inc. of Mountain View, Calif.

Some embodiments of the present invention may be described in the general context of computing system executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that performs particular tasks or implement particular abstract data types. Those skilled in the art can implement the description and/or figures herein as computer-executable instructions, which can be embodied on any form of computing machine readable media discussed below.

Some embodiments of the present invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.

Referring to FIG. 1, the computing system 102 may include, but are not limited to, a processing unit 120 having one or more processing cores, a system memory 130, and a system bus 121 that couples various system components including the system memory 130 to the processing unit 120. The system bus 121 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) locale bus, and Peripheral Component Interconnect (PCI) bus also known as Mezzanine bus.

The computing system 102 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computing system 102 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may store information such as computer readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computing system 102. Communication media typically embodies computer readable instructions, data structures, or program modules.

The system memory 130 may include computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 131 and random access memory (RAM) 132. A basic input/output system (BIOS) 133, containing the basic routines that help to transfer information between elements within computing system 102, such as during start-up, is typically stored in ROM 131. RAM 132 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 120. By way of example, and not limitation, FIG. 1 also illustrates operating system 134, application programs 135, other program modules 136, and program data 137.

The computing system 102 may also include other removable/non-removable volatile/nonvolatile computer storage media. By way of example only, FIG. 1 also illustrates a hard disk drive 141 that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive 151 that reads from or writes to a removable, nonvolatile magnetic disk 152, and an optical disk drive 155 that reads from or writes to a removable, nonvolatile optical disk 156 such as, for example, a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, USB drives and devices, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 141 is typically connected to the system bus 121 through a non-removable memory interface such as interface 140, and magnetic disk drive 151 and optical disk drive 155 are typically connected to the system bus 121 by a removable memory interface, such as interface 150.

The drives and their associated computer storage media discussed above and illustrated in FIG. 1, provide storage of computer readable instructions, data structures, program modules and other data for the computing system 102. In FIG. 1, for example, hard disk drive 141 is illustrated as storing operating system 144, application programs 145, other program modules 146, and program data 147. Note that these components can either be the same as or different from operating system 134, application programs 135, other program modules 136, and program data 137. The operating system 144, the application programs 145, the other program modules 146, and the program data 147 are given different numeric identification here to illustrate that, at a minimum, they are different copies.

A user may enter commands and information into the computing system 102 through input devices such as a keyboard 162, a microphone 163, and a pointing device 161, such as a mouse, trackball or touch pad or touch screen. Other input devices (not shown) may include a joystick, game pad, scanner, or the like. These and other input devices are often connected to the processing unit 120 through a user input interface 160 that is coupled with the system bus 121, but may be connected by other interface and bus structures, such as a parallel port, game port or a universal serial bus (USB). A monitor 191 or other type of display device is also connected to the system bus 121 via an interface, such as a video interface 190. In addition to the monitor, computers may also include other peripheral output devices such as speakers 197 and printer 196, which may be connected through an output peripheral interface 190.

The computing system 102 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 180. The remote computer 180 may be a personal computer, a hand-held device, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computing system 102. The logical connections depicted in

FIG. 1 includes a local area network (LAN) 171 and a wide area network (WAN) 173, but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet.

When used in a LAN networking environment, the computing system 102 may be connected to the LAN 171 through a network interface or adapter 170. When used in a WAN networking environment, the computing system 102 typically includes a modem 172 or other means for establishing communications over the WAN 173, such as the Internet. The modem 172, which may be internal or external, may be connected to the system bus 121 via the user-input interface 160, or other appropriate mechanism. In a networked environment, program modules depicted relative to the computing system 102, or portions thereof, may be stored in a remote memory storage device. By way of example, and not limitation, FIG. 1 illustrates remote application programs 185 as residing on remote computer 180. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used.

It should be noted that some embodiments of the present invention may be carried out on a computing system such as that described with respect to FIG. 1. However, some embodiments of the present invention may be carried out on a server, a computer devoted to message handling, handheld devices, or on a distributed system in which different portions of the present design may be carried out on different parts of the distributed computing system.

Another device that may be coupled with the system bus 121 is a power supply such as a battery or a Direct Current (DC) power supply) and Alternating Current (AC) adapter circuit. The DC power supply may be a battery, a fuel cell, or similar DC power source needs to be recharged on a periodic basis. The communication module (or modem) 172 may employ a Wireless Application Protocol (WAP) to establish a wireless communication channel The communication module 172 may implement a wireless networking standard such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, IEEE std. 802.11-1999, published by IEEE in 1999.

Examples of mobile computing systems may be a laptop computer, a tablet computer, a Netbook, a smart phone, a personal digital assistant, or other similar device with on board processing power and wireless communications ability that is powered by a Direct Current (DC) power source that supplies DC voltage to the mobile computing system and that is solely within the mobile computing system and needs to be recharged on a periodic basis, such as a fuel cell or a battery.

FIG. 2 shows a diagram of an example network environment that may be used with some embodiments of the present invention. Network environment 400 includes user computing systems 205 and 212. One or more of the user computing systems 205 and 212 may be a mobile computing system. The user computing systems 205 and 212 may be connected to the network 250 via a cellular connection or via a Wi-Fi router (not shown). The network 250 may be the Internet. The user computing systems 205 and 212 may be coupled with server computing system 255 via the network 250.

The user computing systems 205 may include application module 208. A user may use the user computing system 205 and the application module 208 to connect to and communicate with the server computing system 255 and login to application 257 (e.g., a salesforce.com® application). The server computing system 255 may be coupled with database 270. The server computing system 255 may be associated with an entity (e.g., salesforce.com®). The user computing system 205 may be used to issue merge requests via a user interface or an API.

FIGS. 3A-3L are example diagrams showing merging of victim nodes to master nodes, in accordance with some embodiments. In general, a request to merge one or more victim nodes to a master node may only be allowed to proceed if a number of constraints are met. As will be described, the constraints may include circular dependency constraint, deleted node constraint and ordering of nodes constraint. For some embodiments, when a request is allowed to proceed, the master node may remain as an active node in its hierarchy after the merge while the one or more victim nodes may be deleted from the system. If the master node has a parent before the merge, then the master node has the same parent after the merge, unless a new parent ID is provided with the merge request. If the master node has no parent before the merge, then the master node also has no parent after the merger, unless a new parent ID is provided with the merge. Further, when a victim node is deleted, its child nodes may be re-parented and become the child nodes of the master node. This may be implemented by updating each of the child nodes with a parent identification (ID) corresponding to the ID of the master node. If the victim node has no children, no re-parenting may be necessary.

Referring to FIG. 3A, three hierarchies 300, 305 and 310 are to be merged based on their respective victim and master nodes. The hierarchy 300 includes a victim node 302, its parent node 301, and its child node 303. The hierarchy 310 includes a victim node 312, its parent node 311, and its child node 313. The hierarchy 305 includes a master node 307, its parent node 306, and its child node 305. The directional line 304 connects the child node 303 of the hierarchy 300 to the parent node 306 of the hierarchy 305 in the direction of parent-child relationship. Similarly, the directional line 309 connects the child node 308 of the hierarchy 305 to the parent node 311 of the hierarchy 310 in the direction of parent-child relationship.

Referring to FIG. 3B, when the victim nodes 302 and 312 are merged to the master node 307, the child node 303 of the victim node 302 and the child node 313 of the victim node 312 become children of the master node 307 in the hierarchy 314. The victim nodes 302 and 312 (shown as dotted lines) may then be deleted from the system. As shown by directional line 304, because the child node 303 is also a parent of the parent node 306, the hierarchy 314 has circular dependency. For some embodiments, the merging of the victim node and the master node may be blocked if the merging results in a hierarchy that includes circular dependency. Based on the resulting circular dependency in the hierarchy 314, the merging request may be blocked. The circular dependency of the nodes is a constraint that the merge request has to satisfy to be allowed to proceed.

Referring to FIG. 3C, the hierarchy 315 includes a victim node 316 and its child nodes 317 and 318. The hierarchy 320 includes a master node 322, its parent node 321 and its child nodes 323 and 324. Directional line 325 shows that the child node 318 of the hierarchy 315 is also a parent of the parent node 321 of the hierarchy 320.

Referring to FIG. 3D, when the victim node 316 is merged to the master node 322, the child nodes 317 and 318 of the victim node 316 become children of the master node 322 in the hierarchy 326. The victim node 316 (shown as dotted lines) may then be deleted from the system. However, as shown by line 325, because the child node 318 is also a parent of the parent node 321, the hierarchy 326 has circular dependency. Based on the resulting circular dependency, the merging request may be blocked. This may be related to the circular dependency constraint.

Referring to FIG. 3E, the hierarchy 330 includes a master node 331 and its child nodes 332 and 333. The hierarchy 335 includes a victim node 337, its parent node 336 and its child nodes 338 and 339. The directional line 340 shows that the child node 333 of the hierarchy 330 is also a parent of the parent node 336 of the hierarchy 335.

Referring to FIG. 3F, when the victim node 337 is merged to the master node 331, the child nodes 338 and 339 of the victim node 337 become children of the master node 331 in the hierarchy 340. The victim node 337 (shown as dotted lines) may then be deleted from the system. Since the hierarchy 340 does not show that the master node 331 having a parent that is a descendant of any of the merged nodes before or after the merging, there is no circular dependency. As such, the merging of the victim node 337 to the master node 331 may be allowed to proceed.

Referring to FIG. 3G, the hierarchy 345 includes a victim node 352, its parent node 346, and its child node 348. The victim node 347 also includes another child node 349 which is designated as a master node (referred to as master node 349). In this example, if the merging is allowed to proceed, the victim node 347 would be deleted. However, because the victim node 347 is a parent of the master node 349, deleting the victim node 347 would cause the master node 349 to have a deleted node as a parent. For some embodiments, the merging of the victim node and the master node may be blocked if the master node is a child node and the victim node is a parent node. The ordering of the victim node and the master node is another constraint that the merge request has to satisfy to be allowed to proceed.

Referring to FIG. 3H, the hierarchy 350 includes a victim node 352, its parent node 351, its child nodes 353 and 354, its grandchild nodes 355 and 356 from the child node 354, its great grandchild node 357 from the grandchild node 355, and its great-great grandchild nodes 358 and 359 from the great grandchild node 357. The great grandchild node 357 is also designated as the master node (referred to as master node 357). For some embodiments, a master node should not be a descendant of any of the victim nodes in a merge request. Verification may be performed to confirm that the master node is not a descendant of a victim node before any merging operation is performed. In this example, the hierarchy 350 shows that the master node 357 is a great grandchild of the victim node 352. As such, the merging request may be blocked. This may be related to the ordering of nodes constraint.

Referring to FIG. 3I, even when the victim node 352 is merged to the master node 357, the merging request may still be blocked due to circular dependency. For example, the child nodes 353 and 354 of the victim node 352 become children of the master node 357 in the hierarchy 360. The grand child nodes 355 and 356 remain with the child node 354. The victim node 352 (shown as dotted lines) may then be deleted from the system. However, as shown by directional line 362, because the grandchild node 355 is also a parent of the master node 357, the hierarchy 360 has circular dependency. Based on the resulting circular dependency, the merging request may be blocked. This may be related to the circular dependency constraint.

FIG. 3J shows an example of a circular dependency of a hierarchy before merging, in accordance with some embodiments. In this example, the hierarchy 370 includes a master node 374 and its parent node 372. The hierarchy 380 includes the victim node 384, its parent node 382 and its child nodes 386 and 388. The child node 388 is also a parent node of the victim node 384 (shown as directional line 376). For some embodiments, the hierarchies associated with the master node and the victim node may be evaluated for circular dependency prior to any merging operation. If the circular dependency exists in either or both of the hierarchies, the merging request may be blocked. This may be related to the circular dependency constraint.

FIG. 4A shows an example of a soft delete node, in accordance with some embodiments. In this example, the hierarchy 400 includes a master node 410, its parent node 405, and its child node 415. The hierarchy 450 includes the victim node 460, its parent node 455 and its child node 465. The victim node 460 also has another child node 470 which, even though has been deleted, still remains in the temporary delete or soft delete status (shown as dotted lines). For some embodiments, a temporarily or soft deleted node may be undeleted to return to a normal or active status. However, a permanently deleted node may not be undeleted.

FIG. 4B shows an example of incorporating a soft delete node in a merge, in accordance with some embodiments. When the victim node 460 is merged with the master node 410, the child node 465 becomes the child node of the master node 410. For some embodiments, the child node 470 may also be linked to the master node 410 as a pseudo child node even though it is in the soft delete status. When the child node 470 is later undeleted, it becomes an active child node of the master node 410, instead of being an orphan node of the deleted victim node 460. FIGS. 4A and 4B also shows a scenario of merging a parented victim node 460 and a parented master node 410, with the master node 410 retaining its parent node 405 after the merging operation, as shown in the hierarchy 480.

It may be possible that both the victim node and the master node are active nodes at the time the merge request is initiated. However, subsequently, one or both of the victim node and master node may be deleted from the system. For some embodiments, verification may be performed prior to any merging operations to confirm that both the master node and the victim node are still active nodes. If one or both of the victim node and master node is deleted, the merge request may be blocked. The deleted node is another constraint that the merge request has to satisfy to be allowed to proceed.

For some embodiments, a merge request may also include a new parent ID for the master node. In such scenario, verification may be performed to confirm that that node associated with the new parent ID is an active node, and not a deleted node, before any merging operation is performed. It is possible that when the request is initiated, the node associated with the new parent ID is an active node; however, it may also be possible that the same node is deleted before the merge operation. If the new parent ID is verified to be associated with a node that has been deleted, the merge request may be blocked because of a potential orphan master node. This may be related to the deleted node constraint.

For some embodiments, verification may be performed to confirm that the node associated with the new parent ID is not a descendant node of the master node. If the new parent ID is verified to be associated with a descendant node, the merge request may be blocked because of potential circular dependency. This may be related to the circular dependency constraint. This may also be related to the ordering of nodes constraint.

FIG. 5 shows an example implementation of a merge module, in accordance with some embodiments. Merge module 500 may be used to receive merge requests and merge a victim node to a master node. The merge module 500 may include a circular dependency verification module 510 configured to verify whether a hierarchy associated with the master node or the victim node includes circular dependency. The circular dependency verification module 510 may also be configured to verify whether a merge of the victim node to the master node may result in a hierarchy that includes circular dependency. If circular dependency is identified by the circular dependency verification module 510, the merge module 500 may block the merge request.

The merge module 500 may include an active node verification module 515 configured to verify whether a node is active or deleted. This may include verifying whether both of the master node and the victim node are active nodes. This may also include verifying whether the parent node associated with the new parent ID included in the merge request is an active node. If any of these nodes is identified by the active node verification module 515 as a non-active node (or deleted node), the merge module 500 may block the merge request.

The merge module 500 may include a re-parenting module 520 configured to re-parent child nodes of a victim node to a master node. Re-parenting a child node may retain the parenting relationship of all descendant nodes of the child node. The re-parenting module 520 may also be configured to re-parent the master node if the merge request includes a new parent ID for the master node.

The merge module 500 may include a soft delete verification module 525 configured to verify whether a victim node is associated with any soft delete child node. If a soft delete child node is identified, the soft delete child node may be re-parented to the master node even though it is not an active node. An example is described with FIGS. 4A and 4B. The merge module 500 may include a victim node removal module 530 configured to remove or delete a victim node from the system when a merge request is allowed to proceed. Although not shown, the merge module 500 may include other modules to enable performing operations to complete a merge request.

FIG. 6A shows a flowchart of an example process for verifying the requirements to merge nodes in hierarchies, in accordance with some embodiments. The process may start at block 605 where the merge request is received. A master node and a victim node may be included in the merge request. At block 610, verification may be performed to determine whether a hierarchy associated with the master node or the victim node includes circular dependency. If circular dependency exists, the merge request may be blocked for failing the circular dependency constraint. If not, the process flows to block 615 where verification may be performed to determine if the master node is a descendant of the victim node in a hierarchy. If that is the case, the merge request may be blocked for failing the ordering of nodes constraint. If not, the process may flow to block 620 where verification may be performed to determine whether the merge request includes a new parent ID for the master node. If a new parent ID is included, verification may be performed to determine if the node associated with the new parent ID is a descendant node of the master node. If that is the case, the merge request may be blocked for failing the circular dependency constraint. If not, the process may flow to block 625 where verification may be performed to determine whether the new parent ID included in the merge request is associated with a deleted node. If that is the case, the merge request may be blocked for failing the deleted node constraint. If not, the process may flow to block 630.

At block 630, verification may be performed to determine whether either of the master node or the victim node is a deleted node. If that is the case, the merge request may be blocked for failing the deleted node constraint. If not, the process may flow to block 635 where verification may be performed to determine whether the merge of the victim node to the master node may result in a hierarchy that includes circular dependency. If that is the case, the merge request may be blocked for failing the circular dependency constraint. For example, when the re-parenting of the child nodes of the victim node to the master node generates circular dependency, the merge process may be stopped and any re-parenting that has been performed may be reversed. For some embodiments, a merge request may need to satisfy each of the circular dependency constraint, deleted node constraint, and ordering of nodes constraint to be allowed to proceed.

FIG. 6B shows a flowchart of an example process for merging nodes after the requirements are satisfied, in accordance with some embodiments. The process 650 may start at block 655 where child nodes of a victim node are re-parented to the master node. If the victim node has no child node, then no re-parenting may be necessary. At block 660, if it is verified that the victim node has a soft delete child node, that child node may also be re-parented to the master node. At block 665, if the merge request includes a new parent ID for the master node, the master node may be re-parented to the node associated with the new parent ID. If the merge request does not include a new parent ID for the master node, then the parent information of the master node may remain the same as before the merge. For example, if the master node was a stand-alone node with no parent before the merge, then the master node remains as a stand-alone node after the merge. If the master node had a parent before the merge, then that parent remains as the parent of the master node after the merge. At block 670, the victim node may be deleted from the system.

For some embodiments, the process of merging the victim node to the master node described above may be implemented using one or more of PL/SQL (Procedure Language/Structured Query Language) and Java of Oracle Corporation. PL/SQL is a procedure extension for SQL and the Oracle relational database. Java is general-purpose programming language designed to have as few implementation dependencies as possible and can run on all platforms that support Java without the need for recompilation. Using a record as a node, FIG. 7 shows some example scripts in PL/SQL to set parent for records, get child records, and get ancestors for record.

FIG. 8A shows a system diagram 800 illustrating architectural components of an on-demand service environment, in accordance with some embodiments. A client machine located in the cloud 804 (or Internet) may communicate with the on-demand service environment via one or more edge routers 808 and 812. The edge routers may communicate with one or more core switches 820 and 824 via firewall 816. The core switches may communicate with a load balancer 828, which may distribute server load over different pods, such as the pods 840 and 844. The pods 840 and 844, which may each include one or more servers and/or other computing resources, may perform data processing and other operations used to provide on-demand services. Communication with the pods may be conducted via pod switches 832 and 836. Components of the on-demand service environment may communicate with a database storage system 856 via a database firewall 848 and a database switch 852.

As shown in FIGS. 8A and 8B, accessing an on-demand service environment may involve communications transmitted among a variety of different hardware and/or software components. Further, the on-demand service environment 800 is a simplified representation of an actual on-demand service environment. For example, while only one or two devices of each type are shown in FIGS. 8A and 8B, some embodiments of an on-demand service environment may include anywhere from one to many devices of each type. Also, the on-demand service environment need not include each device shown in FIGS. 8A and 8B, or may include additional devices not shown in FIGS. 8A and 8B.

Moreover, one or more of the devices in the on-demand service environment 800 may be implemented on the same physical device or on different hardware. Some devices may be implemented using hardware or a combination of hardware and software. Thus, terms such as “data processing apparatus,” “machine,” “server” and “device” as used herein are not limited to a single hardware device, but rather include any hardware and software configured to provide the described functionality.

The cloud 804 is intended to refer to a data network or plurality of data networks, often including the Internet. Client machines located in the cloud 804 may communicate with the on-demand service environment to access services provided by the on-demand service environment. For example, client machines may access the on-demand service environment to retrieve, store, edit, and/or process information.

In some embodiments, the edge routers 808 and 812 route packets between the cloud 804 and other components of the on-demand service environment 800. The edge routers 808 and 812 may employ the Border Gateway Protocol (BGP). The BGP is the core routing protocol of the Internet. The edge routers 808 and 812 may maintain a table of IP networks or ‘prefixes’ which designate network reachability among autonomous systems on the Internet.

In one or more embodiments, the firewall 816 may protect the inner components of the on-demand service environment 800 from Internet traffic. The firewall 816 may block, permit, or deny access to the inner components of the on-demand service environment 800 based upon a set of rules and other criteria. The firewall 816 may act as one or more of a packet filter, an application gateway, a stateful filter, a proxy server, or any other type of firewall.

In some embodiments, the core switches 820 and 824 are high-capacity switches that transfer packets within the on-demand service environment 800. The core switches 820 and 824 may be configured as network bridges that quickly route data between different components within the on-demand service environment. In some embodiments, the use of two or more core switches 820 and 824 may provide redundancy and/or reduced latency.

In some embodiments, the pods 840 and 844 may perform the core data processing and service functions provided by the on-demand service environment. Each pod may include various types of hardware and/or software computing resources. An example of the pod architecture is discussed in greater detail with reference to FIG. 8B.

In some embodiments, communication between the pods 840 and 844 may be conducted via the pod switches 832 and 836. The pod switches 832 and 836 may facilitate communication between the pods 840 and 844 and client machines located in the cloud 804, for example via core switches 820 and 824. Also, the pod switches 832 and 836 may facilitate communication between the pods 840 and 844 and the database storage 856.

In some embodiments, the load balancer 828 may distribute workload between the pods 840 and 844. Balancing the on-demand service requests between the pods may assist in improving the use of resources, increasing throughput, reducing response times, and/or reducing overhead. The load balancer 828 may include multilayer switches to analyze and forward traffic.

In some embodiments, access to the database storage 856 may be guarded by a database firewall 848. The database firewall 848 may act as a computer application firewall operating at the database application layer of a protocol stack. The database firewall 848 may protect the database storage 856 from application attacks such as structure query language (SQL) injection, database rootkits, and unauthorized information disclosure.

In some embodiments, the database firewall 848 may include a host using one or more forms of reverse proxy services to proxy traffic before passing it to a gateway router. The database firewall 848 may inspect the contents of database traffic and block certain content or database requests. The database firewall 848 may work on the SQL application level atop the TCP/IP stack, managing applications' connection to the database or SQL management interfaces as well as intercepting and enforcing packets traveling to or from a database network or application interface.

In some embodiments, communication with the database storage system 856 may be conducted via the database switch 852. The multi-tenant database system 856 may include more than one hardware and/or software components for handling database queries. Accordingly, the database switch 852 may direct database queries transmitted by other components of the on-demand service environment (e.g., the pods 840 and 844) to the correct components within the database storage system 856.In some embodiments, the database storage system 856 is an on-demand database system shared by many different organizations. The on-demand database system may employ a multi-tenant approach, a virtualized approach, or any other type of database approach. An on-demand database system is discussed in greater detail with reference to FIGS. 9 and 10.

FIG. 8B shows a system diagram illustrating the architecture of the pod 844, in accordance with one embodiment. The pod 844 may be used to render services to a user of the on-demand service environment 800.In some embodiments, each pod may include a variety of servers and/or other systems. The pod 844 includes one or more content batch servers 864, content search servers 868, query servers 872, file force servers 876, access control system (ACS) servers 880, batch servers 884, and app servers 888. Also, the pod 844 includes database instances 890, quick file systems (QFS) 892, and indexers 894. In one or more embodiments, some or all communication between the servers in the pod 844 may be transmitted via the switch 836.

In some embodiments, the application servers 888 may include a hardware and/or software framework dedicated to the execution of procedures (e.g., programs, routines, scripts) for supporting the construction of applications provided by the on-demand service environment 800 via the pod 844. Some such procedures may include operations for providing the services described herein. The content batch servers 864 may requests internal to the pod. These requests may be long-running and/or not tied to a particular customer. For example, the content batch servers 864 may handle requests related to log mining, cleanup work, and maintenance tasks.

The content search servers 868 may provide query and indexer functions. For example, the functions provided by the content search servers 868 may allow users to search through content stored in the on-demand service environment. The Fileforce servers 876 may manage requests information stored in the Fileforce storage 878. The Fileforce storage 878 may store information such as documents, images, and basic large objects (BLOBs). By managing requests for information using the Fileforce servers 876, the image footprint on the database may be reduced.

The query servers 872 may be used to retrieve information from one or more file systems. For example, the query system 872 may receive requests for information from the app servers 888 and then transmit information queries to the NFS 896 located outside the pod. The pod 844 may share a database instance 890 configured as a multi-tenant environment in which different organizations share access to the same database. Additionally, services rendered by the pod 844 may require various hardware and/or software resources. In some embodiments, the ACS servers 880 may control access to data, hardware resources, or software resources.

In some embodiments, the batch servers 884 may process batch jobs, which are used to run tasks at specified times. Thus, the batch servers 884 may transmit instructions to other servers, such as the app servers 888, to trigger the batch jobs. In some embodiments, the QFS 892 may be an open source file system available from Sun Microsystems® of Santa Clara, Calif. The QFS may serve as a rapid-access file system for storing and accessing information available within the pod 844. The QFS 892 may support some volume management capabilities, allowing many disks to be grouped together into a file system. File system metadata can be kept on a separate set of disks, which may be useful for streaming applications where long disk seeks cannot be tolerated. Thus, the QFS system may communicate with one or more content search servers 868 and/or indexers 894 to identify, retrieve, move, and/or update data stored in the network file systems 896 and/or other storage systems.

In some embodiments, one or more query servers 872 may communicate with the NFS 896 to retrieve and/or update information stored outside of the pod 844. The NFS 896 may allow servers located in the pod 844 to access information to access files over a network in a manner similar to how local storage is accessed. In some embodiments, queries from the query servers 822 may be transmitted to the NFS 896 via the load balancer 820, which may distribute resource requests over various resources available in the on-demand service environment. The NFS 896 may also communicate with the QFS 892 to update the information stored on the NFS 896 and/or to provide information to the QFS 892 for use by servers located within the pod 844.

In some embodiments, the pod may include one or more database instances 890. The database instance 890 may transmit information to the QFS 892. When information is transmitted to the QFS, it may be available for use by servers within the pod 844 without requiring an additional database call. In some embodiments, database information may be transmitted to the indexer 894. Indexer 894 may provide an index of information available in the database 890 and/or QFS 892. The index information may be provided to file force servers 876 and/or the QFS 892.

FIG. 9 shows a block diagram of an environment 910 wherein an on-demand database service might be used, in accordance with some embodiments. Environment 910 includes an on-demand database service 916. User system 912 may be any machine or system that is used by a user to access a database user system. For example, any of user systems 912 can be a handheld computing system, a mobile phone, a laptop computer, a work station, and/or a network of computing systems. As illustrated in FIGS. 9 and 10, user systems 912 might interact via a network 914 with the on-demand database service 916.

An on-demand database service, such as system 916, is a database system that is made available to outside users that do not need to necessarily be concerned with building and/or maintaining the database system, but instead may be available for their use when the users need the database system (e.g., on the demand of the users). Some on-demand database services may store information from one or more tenants stored into tables of a common database image to form a multi-tenant database system (MTS). Accordingly, “on-demand database service 916” and “system 916” will be used interchangeably herein. A database image may include one or more database objects. A relational database management system (RDBMS) or the equivalent may execute storage and retrieval of information against the database object(s). Application platform 918 may be a framework that allows the applications of system 916 to run, such as the hardware and/or software, e.g., the operating system. In an implementation, on-demand database service 916 may include an application platform 918 that enables creation, managing and executing one or more applications developed by the provider of the on-demand database service, users accessing the on-demand database service via user systems 912, or third party application developers accessing the on-demand database service via user systems 912.

One arrangement for elements of system 916 is shown in FIG. 9, including a network interface 920, application platform 918, tenant data storage 922 for tenant data 923, system data storage 924 for system data 925 accessible to system 916 and possibly multiple tenants, program code 926 for implementing various functions of system 916, and a process space 928 for executing MTS system processes and tenant-specific processes, such as running applications as part of an application hosting service. Additional processes that may execute on system 916 include database indexing processes.

The users of user systems 912 may differ in their respective capacities, and the capacity of a particular user system 912 might be entirely determined by permissions (permission levels) for the current user. For example, where a call center agent is using a particular user system 912 to interact with system 916, the user system 912 has the capacities allotted to that call center agent. However, while an administrator is using that user system to interact with system 916, that user system has the capacities allotted to that administrator. In systems with a hierarchical role model, users at one permission level may have access to applications, data, and database information accessible by a lower permission level user, but may not have access to certain applications, database information, and data accessible by a user at a higher permission level. Thus, different users may have different capabilities with regard to accessing and modifying application and database information, depending on a user's security or permission level.

Network 914 is any network or combination of networks of devices that communicate with one another. For example, network 914 can be any one or any combination of a LAN (local area network), WAN (wide area network), telephone network, wireless network, point-to-point network, star network, token ring network, hub network, or other appropriate configuration. As the most common type of computer network in current use is a TCP/IP (Transfer Control Protocol and Internet Protocol) network (e.g., the Internet), that network will be used in many of the examples herein. However, it should be understood that the networks used in some embodiments are not so limited, although TCP/IP is a frequently implemented protocol.

User systems 912 might communicate with system 916 using TCP/IP and, at a higher network level, use other common Internet protocols to communicate, such as HTTP, FTP, AFS, WAP, etc. In an example where HTTP is used, user system 912 might include an HTTP client commonly referred to as a “browser” for sending and receiving HTTP messages to and from an HTTP server at system 916. Such an HTTP server might be implemented as the sole network interface between system 916 and network 914, but other techniques might be used as well or instead. In some embodiments, the interface between system 916 and network 914 includes load sharing functionality, such as round-robin HTTP request distributors to balance loads and distribute incoming HTTP requests evenly over a plurality of servers. At least as for the users that are accessing that server, each of the plurality of servers has access to the MTS' data; however, other alternative configurations may be used instead.

In some embodiments, system 916, shown in FIG. 9, implements a web-based customer relationship management (CRM) system. For example, in some embodiments, system 916 includes application servers configured to implement and execute CRM software applications as well as provide related data, code, forms, web pages and other information to and from user systems 912 and to store to, and retrieve from, a database system related data, objects, and Webpage content. With a multi-tenant system, data for multiple tenants may be stored in the same physical database object, however, tenant data typically is arranged so that data of one tenant is kept logically separate from that of other tenants so that one tenant does not have access to another tenant's data, unless such data is expressly shared. In certain embodiments, system 916 implements applications other than, or in addition to, a CRM application. For example, system 916 may provide tenant access to multiple hosted (standard and custom) applications. User (or third party developer) applications, which may or may not include CRM, may be supported by the application platform 918, which manages creation, storage of the applications into one or more database objects and executing of the applications in a virtual machine in the process space of the system 916.

Each user system 912 could include a desktop personal computer, workstation, laptop, PDA, cell phone, or any wireless access protocol (WAP) enabled device or any other computing system capable of interfacing directly or indirectly to the Internet or other network connection. User system 912 typically runs an HTTP client, e.g., a browsing program, such as Microsoft's Internet Explorer® browser, Mozilla's Firefox® browser, Opera's browser, or a WAP-enabled browser in the case of a cell phone, PDA or other wireless device, or the like, allowing a user (e.g., subscriber of the multi-tenant database system) of user system 912 to access, process and view information, pages and applications available to it from system 916 over network 914.

Each user system 912 also typically includes one or more user interface devices, such as a keyboard, a mouse, trackball, touch pad, touch screen, pen or the like, for interacting with a graphical user interface (GUI) provided by the browser on a display (e.g., a monitor screen, LCD display, etc.) in conjunction with pages, forms, applications and other information provided by system 916 or other systems or servers. For example, the user interface device can be used to access data and applications hosted by system 916, and to perform searches on stored data, and otherwise allow a user to interact with various GUI pages that may be presented to a user. As discussed above, embodiments are suitable for use with the Internet, which refers to a specific global internetwork of networks. However, it should be understood that other networks can be used instead of the Internet, such as an intranet, an extranet, a virtual private network (VPN), a non-TCP/IP based network, any LAN or WAN or the like.

According to some embodiments, each user system 912 and all of its components are operator configurable using applications, such as a browser, including computer code run using a central processing unit such as an Intel Pentium® processor or the like. Similarly, system 916 (and additional instances of an MTS, where more than one is present) and all of their components might be operator configurable using application(s) including computer code to run using a central processing unit such as processor system 917, which may include an Intel Pentium® processor or the like, and/or multiple processor units.

A computer program product implementation includes a machine-readable storage medium (media) having instructions stored thereon/in which can be used to program a computer to perform any of the processes of the embodiments described herein. Computer code for operating and configuring system 916 to intercommunicate and to process web pages, applications and other data and media content as described herein are preferably downloaded and stored on a hard disk, but the entire program code, or portions thereof, may also be stored in any other volatile or non-volatile memory medium or device, such as a ROM or RAM, or provided on any media capable of storing program code, such as any type of rotating media including floppy disks, optical discs, digital versatile disk (DVD), compact disk (CD), microdrive, and magneto-optical disks, and magnetic or optical cards, nanosystems (including molecular memory ICs), or any type of media or device suitable for storing instructions and/or data. Additionally, the entire program code, or portions thereof, may be transmitted and downloaded from a software source over a transmission medium, e.g., over the Internet, or from another server, or transmitted over any other conventional network connection (e.g., extranet, VPN, LAN, etc.) using any communication medium and protocols (e.g., TCP/IP, HTTP, HTTPS, Ethernet, etc.). It will also be appreciated that computer code for implementing embodiments can be implemented in any programming language that can be executed on a client system and/or server or server system such as, for example, C, C++, HTML, any other markup language, Java™, JavaScript®, ActiveX®, any other scripting language, such as VBScript, and many other programming languages as are well known may be used. (Java™ is a trademark of Sun Microsystems®, Inc.).

According to some embodiments, each system 916 is configured to provide web pages, forms, applications, data and media content to user (client) systems 912 to support the access by user systems 912 as tenants of system 916. As such, system 916 provides security mechanisms to keep each tenant's data separate unless the data is shared. If more than one MTS is used, they may be located in close proximity to one another (e.g., in a server farm located in a single building or campus), or they may be distributed at locations remote from one another (e.g., one or more servers located in city A and one or more servers located in city B). As used herein, each MTS could include logically and/or physically connected servers distributed locally or across one or more geographic locations. Additionally, the term “server” is meant to include a computing system, including processing hardware and process space(s), and an associated storage system and database application (e.g., OODBMS or RDBMS) as is well known in the art.

It should also be understood that “server system” and “server” are often used interchangeably herein. Similarly, the database object described herein can be implemented as single databases, a distributed database, a collection of distributed databases, a database with redundant online or offline backups or other redundancies, etc., and might include a distributed database or storage network and associated processing intelligence.

FIG. 10 also shows a block diagram of environment 910 further illustrating system 916 and various interconnections, in accordance with some embodiments. FIG. 10 shows that user system 912 may include processor system 912A, memory system 912B, input system 912C, and output system 912D. FIG. 10 shows network 914 and system 916. FIG. 10 also shows that system 916 may include tenant data storage 922, tenant data 923, system data storage 924, system data 925, User Interface (UI) 1030, Application Program Interface (API) 1032, PL/SOQL 1034, save routines 1036, application setup mechanism 1038, applications servers 10001-1000N, system process space 1002, tenant process spaces 1004, tenant management process space 1010, tenant storage area 1012, user storage 1014, and application metadata 1016. In other embodiments, environment 910 may not have the same elements as those listed above and/or may have other elements instead of, or in addition to, those listed above.

User system 912, network 914, system 916, tenant data storage 922, and system data storage 924 were discussed above in FIG. 9. Regarding user system 912, processor system 912A may be any combination of processors. Memory system 912B may be any combination of one or more memory devices, short term, and/or long term memory. Input system 912C may be any combination of input devices, such as keyboards, mice, trackballs, scanners, cameras, and/or interfaces to networks. Output system 912D may be any combination of output devices, such as monitors, printers, and/or interfaces to networks. As shown by FIG. 10, system 916 may include a network interface 920 (of FIG. 9) implemented as a set of HTTP application servers 1000, an application platform 918, tenant data storage 922, and system data storage 924. Also shown is system process space 1002, including individual tenant process spaces 1004 and a tenant management process space 1010. Each application server 1000 may be configured to tenant data storage 922 and the tenant data 923 therein, and system data storage 924 and the system data 925 therein to serve requests of user systems 912. The tenant data 923 might be divided into individual tenant storage areas 1012, which can be either a physical arrangement and/or a logical arrangement of data. Within each tenant storage area 1012, user storage 1014 and application metadata 1016 might be similarly allocated for each user. For example, a copy of a user's most recently used (MRU) items might be stored to user storage 1014. Similarly, a copy of MRU items for an entire organization that is a tenant might be stored to tenant storage area 1012. A UI 1030 provides a user interface and an API 1032 provides an application programmer interface to system 916 resident processes to users and/or developers at user systems 912. The tenant data and the system data may be stored in various databases, such as Oracle™ databases.

Application platform 918 includes an application setup mechanism 1038 that supports application developers' creation and management of applications, which may be saved as metadata into tenant data storage 922 by save routines 1036 for execution by subscribers as tenant process spaces 1004 managed by tenant management process 1010 for example. Invocations to such applications may be coded using PL/SOQL 34 that provides a programming language style interface extension to API 1032. A detailed description of some PL/SOQL language embodiments is discussed in commonly assigned U.S. Pat. No. 7,730,478, titled METHOD AND SYSTEM FOR ALLOWING ACCESS TO DEVELOPED APPLICATIONS VIA A MULTI-TENANT ON-DEMAND DATABASE SERVICE, by Craig Weissman, filed Sep. 21, 4007, which is hereby incorporated by reference in its entirety and for all purposes. Invocations to applications may be detected by system processes, which manage retrieving application metadata 1016 for the subscriber making the invocation and executing the metadata as an application in a virtual machine.

Each application server 1000 may be communicably coupled to database systems, e.g., having access to system data 925 and tenant data 923, via a different network connection. For example, one application server 10001 might be coupled via the network 914 (e.g., the Internet), another application server 1000N-1 might be coupled via a direct network link, and another application server 1000N might be coupled by yet a different network connection. Transfer Control Protocol and Internet Protocol (TCP/IP) are typical protocols for communicating between application servers 1000 and the database system. However, other transport protocols may be used to optimize the system depending on the network interconnect used.

In certain embodiments, each application server 1000 is configured to handle requests for any user associated with any organization that is a tenant. Because it is desirable to be able to add and remove application servers from the server pool at any time for any reason, there is preferably no server affinity for a user and/or organization to a specific application server 1000. In some embodiments, therefore, an interface system implementing a load balancing function (e.g., an F5 Big-IP load balancer) is communicably coupled between the application servers 1000 and the user systems 912 to distribute requests to the application servers 1000. In some embodiments, the load balancer uses a least connections algorithm to route user requests to the application servers 1000. Other examples of load balancing algorithms, such as round robin and observed response time, also can be used. For example, in certain embodiments, three consecutive requests from the same user could hit three different application servers 1000, and three requests from different users could hit the same application server 1000. In this manner, system 916 is multi-tenant, wherein system 916 handles storage of, and access to, different objects, data and applications across disparate users and organizations.

As an example of storage, one tenant might be a company that employs a sales force where each call center agent uses system 916 to manage their sales process. Thus, a user might maintain contact data, leads data, customer follow-up data, performance data, goals and progress data, etc., all applicable to that user's personal sales process (e.g., in tenant data storage 922). In an example of a MTS arrangement, since all of the data and the applications to access, view, modify, report, transmit, calculate, etc., can be maintained and accessed by a user system having nothing more than network access, the user can manage his or her sales efforts and cycles from any of many different user systems. For example, if a call center agent is visiting a customer and the customer has Internet access in their lobby, the call center agent can obtain critical updates as to that customer while waiting for the customer to arrive in the lobby.

While each user's data might be separate from other users' data regardless of the employers of each user, some data might be organization-wide data shared or accessible by a plurality of users or all of the users for a given organization that is a tenant. Thus, there might be some data structures managed by system 916 that are allocated at the tenant level while other data structures might be managed at the user level. Because an MTS might support multiple tenants including possible competitors, the MTS should have security protocols that keep data, applications, and application use separate. Also, because many tenants may opt for access to an MTS rather than maintain their own system, redundancy, up-time, and backup are additional functions that may be implemented in the MTS. In addition to user-specific data and tenant specific data, system 916 might also maintain system level data usable by multiple tenants or other data. Such system level data might include industry reports, news, postings, and the like that are sharable among tenants.

In certain embodiments, user systems 912 (which may be client machines/systems) communicate with application servers 1000 to request and update system-level and tenant-level data from system 916 that may require sending one or more queries to tenant data storage 922 and/or system data storage 924. System 916 (e.g., an application server 1000 in system 916) automatically generates one or more SQL statements (e.g., SQL queries) that are designed to access the desired information. System data storage 924 may generate query plans to access the requested data from the database.

Each database can generally be viewed as a collection of objects, such as a set of logical tables, containing data fitted into predefined categories. A “table” is one representation of a data object, and may be used herein to simplify the conceptual description of objects and custom objects according to some embodiments. It should be understood that “table” and “object” may be used interchangeably herein. Each table generally contains one or more data categories logically arranged as columns or fields in a viewable schema. Each row or record of a table contains an instance of data for each category defined by the fields. For example, a CRM database may include a table that describes a customer with fields for basic contact information such as name, address, phone number, fax number, etc. Another table might describe a purchase order, including fields for information such as customer, product, sale price, date, etc. In some multi-tenant database systems, standard entity tables might be provided for use by all tenants. For CRM database applications, such standard entities might include tables for account, contact, lead, and opportunity data, each containing pre-defined fields. It should be understood that the word “entity” may also be used interchangeably herein with “object” and “table”.

In some multi-tenant database systems, tenants may be allowed to create and store custom objects, or they may be allowed to customize standard entities or objects, for example by creating custom fields for standard objects, including custom index fields. U.S. Pat. No. 7,779,039, titled CUSTOM ENTITIES AND FIELDS IN A MULTI-TENANT DATABASE SYSTEM, by Weissman, et al., and which is hereby incorporated by reference in its entirety and for all purposes, teaches systems and methods for creating custom objects as well as customizing standard objects in a multi-tenant database system. In some embodiments, for example, all custom entity data rows are stored in a single multi-tenant physical table, which may contain multiple logical tables per organization. In some embodiments, multiple “tables” for a single customer may actually be stored in one large table and/or in the same table as the data of other customers.

These and other aspects of the disclosure may be implemented by various types of hardware, software, firmware, etc. For example, some features of the disclosure may be implemented, at least in part, by machine-readable media that include program instructions, state information, etc., for performing various operations described herein. Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher-level code that may be executed by the computer using an interpreter. Examples of machine-readable media include, but are not limited to, magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD-ROM disks; magneto-optical media; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory devices (“ROM”) and random access memory (“RAM”).

While one or more embodiments and techniques are described with reference to an implementation in which a service cloud console is implemented in a system having an application server providing a front end for an on-demand database service capable of supporting multiple tenants, the one or more embodiments and techniques are not limited to multi-tenant databases nor deployment on application servers. Embodiments may be practiced using other database architectures, i.e., ORACLE®, DB2® by IBM and the like without departing from the scope of the embodiments claimed.

Any of the above embodiments may be used alone or together with one another in any combination. Although various embodiments may have been motivated by various deficiencies with the prior art, which may be discussed or alluded to in one or more places in the specification, the embodiments do not necessarily address any of these deficiencies. In other words, different embodiments may address different deficiencies that may be discussed in the specification. Some embodiments may only partially address some deficiencies or just one deficiency that may be discussed in the specification, and some embodiments may not address any of these deficiencies.

While various embodiments have been described herein, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present application should not be limited by any of the embodiments described herein, but should be defined only in accordance with the following and later-submitted claims and their equivalents. 

What is claimed is:
 1. A computer-implemented method to merge nodes in hierarchies, the method comprising: receiving, by a database system, a request to merge a first node in a first hierarchy of a plurality of nodes into a second node, the first node in the first hierarchy having child nodes; determining, by the database system, whether the merge request violates each of a plurality of constraints, the plurality of constraints comprising circular dependency of nodes, deleted node and ordering of nodes; and re-parenting, by the database system, in response to a determination that the merge request does not violate each of the plurality of constraints, the child nodes of the first node in the first hierarchy of nodes to the second node in response to the merging of the first node into the second node.
 2. The method of claim 1, wherein the merge request violates the ordering of nodes constraint when the second node is a descendant of the first node.
 3. The method of claim 2, wherein the merge request violates the deleted node constraint when the first node or the second node is a deleted node.
 4. The method of claim 3, wherein, based on the merge request including a new parent identification (ID) for the second node, the merge request violates the ordering of nodes constraint when a node associated with the new parent ID is a descendant of the second node.
 5. The method of claim 4, wherein the merge request violates the deleted node constraint when the node associated with the new parent ID is a deleted node.
 6. The method of claim 5, wherein the merge request violates the circular dependency constraint when the first node or the second node is associated with a hierarchy having circular dependency or when said merging the first node to the second node generates a hierarchy having circular dependency.
 7. The method of claim 6, wherein said re-parenting the child nodes of the first node to the second node includes re-parenting a soft delete child node of the first node to the second node.
 8. The method of claim 7, further comprising deleting, by the database system, the first node based on the merge request being allowed to proceed.
 9. An apparatus comprising: one or more processors; and a non-transitory computer readable medium storing a plurality of instructions, which when executed, cause the one or more processors to: receive a request to merge a first node in a first hierarchy of a plurality of nodes into a second node, the first node in the first hierarchy having child nodes; determine whether the merge request violates each of a plurality of constraints, the plurality of constraints comprising circular dependency of nodes, deleted node and ordering of nodes; and re-parent, in response to a determination that the merge request does not violate each of the plurality of constraints, the child nodes of the first node in the first hierarchy of nodes to the second node in response to the merging of the first node into the second node.
 10. The apparatus of claim 9, wherein the merge request violates the ordering of nodes constraint when the second node is a descendant of the first node.
 11. The apparatus of claim 10, wherein the merge request violates the deleted node constraint when the first node or the second node is a deleted node.
 12. The apparatus of claim 11, wherein the merge request violates the ordering of nodes constraint when the merge request includes a new parent identification (ID) for the second node, and wherein a node associated with the new parent ID is a descendant of the second node.
 13. The apparatus of claim 12, wherein the merge request violates the deleted node constraint when the node associated with the new parent ID is a deleted node.
 14. The apparatus of claim 13, wherein the merge request violates the circular dependency constraint when the first node or the second node is associated with a hierarchy having circular dependency or when said merging the first node to the second node generates a hierarchy having circular dependency.
 15. The apparatus of claim 14, wherein said instructions to re-parent the child nodes of the first node to the second node include instructions to re-parent a soft delete child node of the first node to the second node.
 16. The apparatus of claim 15, further comprising instructions, which when executed, cause the one or more processors to delete the first node based on the merge request being allowed to proceed.
 17. A computer program product comprising computer-readable program code to be executed by one or more processors when retrieved from a non-transitory computer-readable medium, the program code including instructions to: receive a request to merge a first node in a first hierarchy of a plurality of nodes into a second node, the first node in the first hierarchy having child nodes; determine whether the merge request violates each of a plurality of constraints, the plurality of constraints comprising circular dependency of nodes, deleted node and ordering of nodes; and re-parent, in response to a determination that the merge request does not violate each of the plurality of constraints, the child nodes of the first node in the first hierarchy of nodes to the second node in response to the merging of the first node into the second node.
 18. The computer program product of claim 17, wherein the merge request violates the ordering of nodes constraint when the second node is a descendant of the first node.
 19. The computer program product of claim 18, wherein the merge request violates the deleted node constraint when the first node or the second node is a deleted node.
 20. The computer program product of claim 19, wherein the merge request violates the circular dependency constraint when the merge request includes a new parent identification (ID) for the second node, and wherein a node associated with the new parent ID is a descendant of the second node.
 21. The computer program product of claim 20, wherein the merge request violates the deleted node constraint when the node associated with the new parent ID is a deleted node.
 22. The computer program product of claim 21, wherein the merge request violates the circular dependency constraint when the first node or the second node is associated with a hierarchy having circular dependency or when said merging the first node to the second node generates a hierarchy having circular dependency.
 23. The computer program product of claim 22, wherein the program code to re-parent the child nodes of the first node to the second node includes program code to re-parent a soft delete child node of the first node to the second node.
 24. The computer program product of claim 23, the program code including further instructions to delete the first node based on the merge request being allowed to proceed. 